docs: def kml_element_name(grid_coords, elem_id="KML"):
      """
      Create a unique element name for KML
  
      Args:
          grid_coords (GridCoordinate):
          elem_id (str):
  
      >>> kml_element_name(GridCoordinate(zoom=5, x=42, y=60), elem_id="NL")
      'NL_5_42_60'
      """
      return "_".join(str(x) for x in [elem_id, grid_coords.zoom, grid_coords.x, grid_coords.y])